#!/usr/bin/etc/python3
# -*- coding: utf-8 -*-

s = set([1, 2, 3, 3])
print(s)

s.add(4)
s.add(4)
print(s)

s.remove(4)
print(s)

s1 = {1, 2}
s2 = {2, 3, 4}
print(s1 & s2)
print(s1 | s2)